Investigators have pulled from a retention pond a car belonging to a 17-year-old Illinois girl who vanished earlier this month while on her way to a work holiday party.

Brissa Romero’s Nissan Rogue was found in the pond not far from the fast food restaurant where she was last seen, but Romero was not inside, WFLD reported.

Vernon Hills Police Chief Patrick L. Kreis said that investigators believe Romero was inside when the vehicle went into the pond, however.

“As the first supervisor showed up on the scene to search the area, he met a resident who had been walking around the bank of this pond, and she pointed out a backpack that seemed to have floated on the edge of the pond,” said Kreis.

The pond is about 20 feet deep at its deepest point, and that’s where the Nissan was found, the chief said.

“The vehicle traveled as much as 60 feet into the pond,” he said. “It really appears that this is a case where the driver, unfamiliar with the area, failed to navigate a turn and went through the intersection, down the embankment into the pond.”

Romero disappeared on December 4 while on her way to the party, as CrimeOnline reported. She was last seen, on surveillance footage, at the fast food restaurant, where she was seen entering and the leaving a short time later. She got into her vehicle and drove away. Her cell phone last pinged less than 15 minutes later not far from the retention pond.

Romero’s sister, Dulce Romero, said at a news conference on Monday that she is holding out hope.

“I still believe that she’s out there,” she said.

“If Brissa is listening to this right now, all of your family is really worried, we want to hear that you’re okay, your mom is desperate, too,” said the girl’s aunt, Yeni Montilla.

Romero, who attended Harper College, was studying to be a sonogram nurse and working two jobs to pay for school.

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[Featured image: Brissa Romero/WMAQ Video Screengrab]